Underfeed stoker



' May 17, 1927. 1,629,283

E. LUNDGREN UNDERFEED STOKER Filed Feb. 23, 1924 INVENTOR ATTORNEYS Patented May 17, 1927.

PATENT orries.

UNITED STATES IBUSTION ENGINEERING GOR PORATION,

I nnmwazen.

OENEW YORK, N. Y., A CORPORATION OF UNDEBFEED s'roxnn;

, Application filed February 23, 1924. Serial No. 694,484.

My invention relates to underfeed stokers, and has special reference to underfeed stokers of the type having a plurality of downwardly' and rearwardly inclined retorts having longitudinallymovable side walls and tuyere structures mounted upon the side walls. V I v In stokers of this type, as heretofore'constructed, the feeding of the fuel throu h the retorts and into the furnace depen s entirely upon the feeding action of the primary ram at the forward end of each retort, and the action of the tuyere structures carried by the side walls to drag the fuel out from the retorts and distribute it over the tuyere structures. This action is not very positive and becomes aggravated as the length of the stoker is increased.

Another disadvantage of stokers of this 204 type as heretofore provided, is that with the use of coking fuels, the fuel cokes in a mass in the retort during banking hours and there is no means to break up thls coke formation when the stoker is again started without resorting to bars or other make shifts to-do so. The object of the present invention is to overcome the disadvantagesabove referred to of underfeed stokersof the type indicated, as will hereinafter appear.

a drawings is of the No. 1,322,822, dated Nov. 25, 1919; Asshown this stoker comprises an underfeed grate 2, and an overfeed grate fat the rear thereof. The underfeed grate comprises a plurality of downwardly and rearwardly in clined retorts -6 arranged side by side and spaced apart with the outer walls of the outer retorts spaced from the side walls of The following is a description of my im 1 trated and described in the Patent to Riley the fire box of the furnace. Each of the retorts isprovided with a bottom wall 8 and The bottom walls 8 of the side walls 10.- a several retorts form continuations of the bottom walls, respectively, of fuel hoppers 12, the fuel'fromthe hoppers being fed into theretorts by means of horizontally reciprocatmgplungers or rams 16. On the upper edge .of each of the side walls of the retorts is mounted a. row of tuyere blocks 18, the

rows of tuyere blocks mounted on the adja--. cent walls of the retorts being arrangedside' by side with their inner. surfaces in sliding engagement, and the rows of tuyere blocks mounted on the outer walls of the outer retorts extending over the spaces between the outer walls and the side walls of the 'fire box of the furnace. The overfeed grate 4 is made up of aplurality of sections arranged side by side, each of which is associated with one of the side walls of one of the retorts, and these parts together with the row of tuyere blocks mounted on the sidewall are adapted to be moved togetheras a' unit back and forth in a substantially horizontal direction. to assist in feeding the fuel pro gressively while in the course of combustion rearwardly of the furnace. and to discharge the ref-use of'the fuel in the usual ash pit located at the rear of the overfeed grate. To enable said units to be this moved back and forth each overfeed grate section is mounted on a shoe 22 adapted to slide horizontally on a support 24, the lower or rear end of the associated retort side wall being pivotally connected at 26 to the shoe and Its upper or forward end being suitably mounted for sliding movement. The means for actuating the several movable units above described comprise links 28 connecting the forward ends of the walls of each retort with the reciprocating feeding plung or or ram 16 associated with the retort.

"@Exceptas hereinafter described, the

parts above referred to may be and preferably are the same as the corresponding parts of the stoker illustrated and described in said patenttov Riley No. 1,322,822 to which reference may complete description of the same.-

In the embodiment of'the present invention illustrated in the drawings each side wall carries a plurality 'of fuel agitating be had for a more- CJI art, my invention permits of various modiand feeding members 30, the members on the side walls of each retort extending horizontally substantially to. the center line of the retort and the members on the two side Walls being spaced different distances from the bottom of the retort and'being arranged instaggered relation. Each member is wedge-shape in cross section and has one of its faces directed rearwardly of the retort. The members may be removably secured to the side walls by means of bolts 32 as shown in Fig. 2 so as to enable them to be easily removed-and replaced as desired, or may be cast integral with the side walls, as shown in Fig. 3, in the latter figure one ofvsaid members is indicated at 30 and one of the side walls of the retort is indicated at 10. 7

With this construction it will be apparent that during the operation of the stoker the members 30 will positively act throughout the length of the retort: to cooperate with the tuyere rtructures carried by the side walls to uniformly feed the fuel down the retorts and distribute. it over the tuyere structures. It will also be apparent because of the wedge-shape construction of the members 30 that when'the stoker is started after bein banked, the members will act immediately to agitate'the fuel and thoroughl break up any coke formation with-- in the retort. Under certain'conditions it might be desirable to decrease the areas of the fuel pushing faces of the members 30 toward the rear end of the retort, and also the number and relative positions of the members employed can be made to suit. the

requirements of various fuels.

As will be evident to those skilledin the fications without departing from thespirit thereof orthe scope of the appended claims. 'hat I clai1'n is: 1

1. A furnacehaving, in combination, a downwardly and rearwardly inclined retort having sidewalls longitudinally movable, means for reciprocating said side walls longitudinally and for feeding fuel into the forward end of the retort, and members carried by said slde Walls andextendmg transversely of the retort for acting on the fuel therein, each'of said members being of having side walls longitudinally movable,

means for reciprocating saidside' Walls longitudinally and for feeding fuel into the forward end of the retort, and devices carried by at least one of the sidewallsfor acting on the fuel within the retort substan tially throughout the length thereof during said movement of said side walls, said devices being arranged one in front of the other and spaced apart, and each of said devices having a fuel pushing face directed toward ,the rear of the furnace.

A furnace having, downwardly and rearwardly inclined retort having-side Walls longitudinally movable, means for reciprocating-said side Walls longitudinally and for feeding fuel into the forward end of the retort, and laterally proecting members carried by each of the sidewalls, spaced a distance apart longitudinally of the side walls, and with the mner ends of the members on the two side Walls arranged in close proximity to the same vertical plane,

and having rearwardly directed fuel propelling faces forfeeding the fuel down the retort.

EDWIN LUNDGRE N.

in combination, a 

